Gear finishing machine



Apfil 14, 1942. v w; MILLER 2,280,045 GEAR FINISHING MACHINE Filed June 19, 1936 6 Sheets -Sheet 1 172M772 j mmmw April14,,-1942. E. W. ILLER 2,280,045

GEAR FINISHING MACHINE Filed June 19, 1936 s Sheets-Sheet 2 e: fl 5e %\l W a! P '9 I L 7 I I I s J IP -:e' I 1 7 I e {a pril m, 1942. EQWQ MILLER 2 280,0 5

GEAR FINISHING MACHINE Filed June 19, 1936 G'Sheets-Sheet 3 April 14 1942;

E. w. MILLER 2,280,045

GEARFINISHING MACHINE Filed June 19, 1956 I 6 Sheets- Sheet 4 if v April 14, 1942. E. w. M iLLER 2,280,045.

GEAR FINISHING, MACHINE Filed June 19, 1936 6 Sheets-Sheet 5 6* I J/ mwmw ke I Jim April 14, 1942. E. w. MILLER 2,280,045

GEAR FINISHLNG MACHINE I Filed June 19, 1936 6 S hegts-Sheet 6 440 ,/Z-'-F"-. n

Patented Apr. 14,1942

@STAT ES 7 P TE T;lorries GEAR "Madame" I J r i e lidv'vard W. Miller, Springfield, "Vb," assignorto I The Fellows Gear ShaperCompany,Springfield,

l -:,"Vt.,acorporation ofVermbntr I .f lpplieation 11111019, isaa'seriai'niisaoae (o .9'o+1.e)

. x zooiaims. The presentinvention'relates to rnachines for finishing gears with theaid of a tool having teeth of conjugate forn to thejteeth of thework gear, and by which relative motions between the tool and work gear are effected, compounded of rotation in mesh. with one another ,and relative reciprocation inithedirection oithe axis of the work gear. It is mvpresent objectto provide a machine of" this character havingfimeans for mounting and operating such a tool and work i gear in associa'tionlwith oneanother. A further object is to provide ineansifor adapting such a machine to a widei variety of, uses, such as that of finishing either 'external or internal gears by a tool having external teeth, or an external gear by a tool with internalteeth; and id finish helical gears, either fexternalj orinternal, by a tool'hav ing either straighflor helical teeth, 'or straight toothed gears by a helical' 'tool. V

*The invention cornprehends the means and combinations of elements, hereinafter described, for carrying slichq'objects into effect, together with all novel principles.thereofr'and all equivalent structures containing 7 such principles, vvithin thescoped-the appended'claims as ,construed in the'light'oi the 'prior' art. v This applicationis a continuation 'in'fpart of the patent application filedf by. me November 19, 1935', Serial ,No. 50,57 3, entitledMethod and rneans for finishing gears, on: whichf l'lietters Patent No. 2,228,965 weregrantedIJanu ary 14 1941, andin cludes, a number" of improvements and useful features additional to the rnatt'ers disclosed in said application. I f

A specific cornmercialinachine ernbddying the. principlesffor ,which I I 'seekprotectionfiis dein the drawin'gsdn which scribed in 't'he following and shown taken through the,axes of theitool spindle and thework piece'lon the line'Ilf-T offr'f g. l6 i Fig; 2 is inlpart a lfrpnt elevation and impart a verticalsection takenpnline 21-2 of Fig[ 1;

Fig. 3 is'a .detailfcrossfseetion taken on line Fig. 415 avertical section ltalrenfon line 44 of lffig. land a rear elevation of the,upper part of thelmachi'ne;

. Fig. 5 is arear elevation of theentire rnachine'; Fig. f6? is a horizontal [section on line 6--6 of and adjacent parts of 'thernachinei Fig. 1 and a,planlvievvofi theparts below the "Fig.3 is adetail"viewin section oi'a 'camI by I which the work holder is operated, shown with Fig. 11. is air'agmentary horizontal section and plan view similar to Fig. 6 but showing an adjustment ofthe machine for a specifically differentchaiacter of Work. i

'Fig. '12 is a partial side elevation of a tool forming part of the, machine combination adapted to 'finishinternal helical gears;

Fig. '13 is a "partial section of an equivalent tool having internal t'e'eth adapted to finish external helical 'g ea'rs';

i Fig. 14 'is a ir'agmentarr elevation of an external tool for finishing external helical gears; Y

Fig. 15 is, a fragmentaryelevation of an external helical tool adapted to finish "spurgea'rs.

. \l'iike reference' character s designate the same parts wherever they'oc'cur' in" all the figures.

Thefrnachine structure comprises 'a base or 'pedestalfl'Z, on the top of which is secured a guide block Pi supporting a sliding'carriage M. The carriage rests on 'guideways 15 of the guide block 13'and'ha'sfiangesl1 and 'gibsfilja embracing ledges". 19 on the "opposite sides of the guide block." There is secured adjustably, with" "provision for angular adjustment, onthe "carriage I G, a holder"'2fl in which a spindle 21 is ,rotatably mounted. For conyenience inthepresentdescription the spindle 2i will be called the tool spindle, although it will presently beshown'that the same spindle may carry a workgear instead of a tool; and for the same 'reasonthe holder 20 ,Willbe called the tool holder and the carriage M the tool carriage. On thetop of the holder 28 is mounted an electric "motor 22 which drives the spindle?! through pulleys or;sprocket's 23*, 24, and a belt or. chain 25,*shaft 26,gearsI21 ,-'28.

jshaft29', arranged as shown in Fig. lyand 1 ohange gears' 30 and 31 on the last named shaft r and on the tool spindle respectively. The specific drive thusshown typifies any driving means suitable for the purpose and is not to-be construed as a limitation of the invention in that respect.

The machine as set'up in Figs. I -10. inclusive is organized tofinish an internal helical gear 32 by thecutting and ;burnishing action of a gear-like tool 33 operated in mesh withthe work gear and with, its axis aske'w tofthat of the work gear. The tool represented injthese figures and shown on a larger 'scalein Fig. 12, is an embodimenu of. the "tool, described and claimed in my modified "form of faces of the teeth are longitudinally convex on f j,

both sides, as shown in Fig. 12 (with exaggeration for clarity), in order to permit the cutting edges and the areas of the side facesadjacent thereto to engage the teeth of the work gear, as

fully explained in my prior applications. Such teeth may be either parallel to the axis of the tool and spindle, or helical with a different helix angle than that of the Work gear teeth. But other tools may be used here if desired, including those which lap or .burnish only as well as tools like those of my preceding application..

The spindle holder'20 is adjustable angularly in a horizontal plane about a vertical axis A (Figs. 6 and 11) in front of the sliding carriage l4, and the spindle 2| protrudes from the holder perpendicular to and in axial intersection with the axis A; and it is suitably constructed to mount the tool units symmetrically at opposite sides of the axis A, wherefore angular adjustments of the holder change only the angular relationship of the tool, and not its position with respect to the path of its travel. An undercut groove 34 of arcuate curvature, concentric with axis A, is provided in the upper side of the carriage I4, and the holder is equipped with guide rolls 35 projecting fromits under side which bear on the opposite edges of this groove, as shown in Fig. 1, and with clamps 36 underlapping the sides of thegroove,equipped with screws and nuts 3'! for securing the holder in place; Additional securing means are afforded by the slotted flanges 38'at opposite sides of the rear part of the holder, in which the slots 39 are also concentric to the axis A, and through which pass clamping bolts 40 screwed into holes in the carriage. Provision of a sufficient number of such holes, some of whichare shown at 4| in Fig. 6, together with a suitable length of the slots 39, enables the spindle 2| 'to be, set either parallel to the path of movement of the carriage or at any angle within a wide range to either side of such parallel position.

The work support (so called'for present convenience although, as will' presently appear, it may serve also as a tool support), comprises a slide 43 vertically movable in guideways 44 on the forward side .of the base, and a holder 45 secured to the upper end of said slide. Different holders may be substituted for one another, for which purpose the slide is provided with a wide table-like portion '46 at its upper end adapted to receive work or tool holders of different kinds in different positions. The slide is adapted to be adjusted vertically to accommodate such different holders, and thework pieces or tools carried thereby, to the spindle 2 I; and inthe operation of themachine the'slide is alsor'aised and lowered automatically. "It is equipped with a plunger 41. located and sli'dable longitudinally in a passageway in its'interior and withheld from rotation by a key 48,]The lower end of such plunger carries a cam follower r0ll'49 engaging a cam by which theautomatic rise and descent of the slide in prescribed timing with the other is fitted rotatably in the passageway and supports the slide through a thrust bearing 53 and a cover plate or block 54 secured to the upper end of the slide across the passageway. Rotation of the nut to adjust the slide up or down is effected manually by a worm or helical gear 55 meshing with a series of worm gear teeth Won the nut and secured to a shaft 5'! which is rotatably mounted in, and protrudes from the front of, the slide and may be rotated by a wrench.

The work holder 45 shown in Figs. 1, 2, 6 and '7 is designed to support rotatably an internal helical gear. Its base rests on the table 46, whereon it is positioned by a rib 58 (secured to the table top) and made fast by screws 59 entering tapped holes in the table. The'upright portion ofthe support has a circular aperture in which is supported rotatably (by ballbearings 60 or in any other suitable manner) an annular carrier Si in which the work piece 32 is secured by an adapter 62 and clamps 63. The specific character of the work carrier, gripping means and support here shown is of minor importance, inasmuch as many different designs of work supporting means may be used adapted to hold work pieces of different kinds and dimensions.

In the operation of the machine, the carriage I4 is reciprocated in the path to which it is constrained by the guide block I3, such path, and the position of the work support, being so related as to cause traverse of the tool 33 across the face of the work gear in parallel with the rotational axis of the latter. It may be noted further that the work holder is so placed as to bring a diametral plane of the work piece into coincidence with the axis A, and to cause mesh of th tool and Work gear to occur in this plane. The mechanism for thus reciprocatingthe carriage comprises a crank disk 64 carrying a radially adjustable crank pin 65, which may be located in the axis of the disk, or at any point between such axis and either end of the diametral slot in the disk, and a connecting rod 66 coupled to the carriage by a wrist pin 61 (Fig. l). The crank disk is secured to the upper end of an upright shaft 68 which is driven by an electric motor 69 (Fig. 5) through a belt and pulley drive 10, H, 72, shaft 13, worm-and wheel drive 14, 15, shaft 16 (Fig. 4), worm and wheel drive 11, 18, shaft 19, change gears 80, 8|, shaft 82-and worm and wheel drive 83, 84, the last element of which is keyed to shaft 68. Within the'meaning of the the worm and wheel applied to the gears here described are included equivalent helical gear pairs,either member of'which may be a throated gear. This train is designed to reciprocate the carriage at a relatively slow rate while the spindle 2| is driven at high speed.

' The cam 50 which controls the rise and descent of slide 43 is rotated in time with'the crank shaft 58 at a suitable speed ratio. Itis keyed to a shaft 85 which is driven from shaft 16 by a worm and wheel drive 86, 87 (or equivalent helical gears), shaft 88 and change gears 89 and 90 secured to the shafts 88 and 85 respectively. The cam permits a separation of the work from the tool radially of the latter when the tool is at one longitudinal curvature aiaeogo lt limit offits traversing" movement, whereforeit is fbrme'd with a depressionfii which-is located to receiveflthe" follower roll when thetoo'l is withdrawn, i. e., when thecrank' pin65 is at its rear dead; point. The: cam si'irface at the side of the depression which" advances when the machine" starts is designed to effect a quick rise of the slide andf'eeding of the work into full depth of mesh with thejtool". At the ehdbf one rotation,

' during which the tool has" traveled forward and back, the follower enters the depression and permits withdrawal of the work. t

,This cam is" located outside of the adlacent wall" of the basewhere" it is accessible for removal and substitution of equivalent cams havin specific characteristics for definite purposes. such substitutions are readily made by removing the nut andshown in Fig. l and'siippinthe the teeth narrower in. mid length than at the ends, with longitudinal concavity in their side faces. The bowed curvatures thus produced in thework gear teeth are essentially like those of the tool teeth explained in my before mentioned prior. applications Serial No. 50,573 and Serial No. 74,614. Theyenable' gears which are meshed together with their axes askew to one another to have an extended bearing lengthwisawhich may continue throughout the entire overlapping length of the meshing gear teeth or may be any desired fractionof suchov'erlapping length depending on the degree, of longitudinal convex curvature. Internal-external skew gear couples have such extended bearing when the teeth of either mem'ben'of the-couple are longitudinally convex on both sides; while the same character of bearing is obtained between two external gears in skewed mesh when the teeth of either are made concave longitudinally on both faces. Bowed formations of this general nature are useful for other purposes also.

Such a convex formation is obtained with the aid" of the embodiment of cam 50' shown in Fig. 8.

. Such cam is provided withv high dwells a and b of equal radius, beside the notch 9|, another high dwell c of the same radius at the opposite side of thecam, and intermediate arcs d and e of progressively and symmetrically decreasing and increasing radius, located oppositely to one another. By this cam the work carriage is caused to descend and rise gradually in the course of each stroke of the tool, and is held at its highest point at the ends of the stroke. Thus the depth of cut made by the tool is greatest at the ends of the work gear teeth and is gradually of less depth from each end to the middle. 1 To obtain the concave bowed effect, a cam embodiment such as that shown in Fig; 9 is used,which has low dwells a, b at one side of its center and c at the opposite side of equal radius, and intermediate eccentric segments (if and e of gradually increasing and decreasing radii, by which the work is raised toward the middle of each stroke of the tool and lowered as the tool approaches the ends of the strokes. According as greater or less of thegr'eatest andleast depths of out are desiredin other parts of the gear teeth, the character and location of the" cam rises and descents are appropriately varied. If uniform tooththick ness is required a cam of'unifern-r radius, except at the depression 91', is used. i

The cycle of this machine, in the course or which it completesthefinishing operation on a gear, is designed to consist of one reciprocation forward andback of the tool, and one rotation of the cam 50. Means are provided for stopping the motors 22 and 69 at the end of each cycle, consisting" of a cam 9 2 on the shaft 88 controlling the motor 22' through a switch mechanism 93 and a cam disk 94 secured adjustably to the camel] for controlling the motor 69 through a switch mechanism 95. These are control devices of conventional character, and the machine may be startedby other suitable controlmeans of knowntype which need no illustration.

1' have explained in my prior application Serial No. 50,573 (Patent 2,228,965) that finish-i'ngoperations such as this machine is designed tov effect may be carried outon either external or internal 9 gears by an externally toothed tool; and may also be performed on external gears by an internally toothed tool. It is part of the invention to make the machine adjustable or convertible so as to carry out all of such operations. The means to this end comprise provisions for substituting not only different external tools for the tool 33', but also for the substitution of an external work gear on the spindle" 2t, and the substitution of other holders for the work holder 45 adapted to mount work gears, either internal or external, of

different dimensions; and also to mount an internall'y toothed tool in position to mesh with a work" gear on the spindle 2!, at askew angle, when the spindle is adjusted into parallelism with the'path of movement of the carriage I4. When work of the character herein discussed isperformed withdistribution of the cutting effect by relative translation between the tool and work, it is essential that such translation take place in a line parallel tothe axis of the work. Hence when the workpiece is mounted on theslide 43, it is arranged with its axis parallel to the path of the carriage M; and when the tool is mounted on slide 43 and the work piece on spindle 2 I, the holder 2!! is adjusted to bring the toothed tool Hill is secured coaxially in the carrier i and is provided with cutting edges and rubbing faces on its teeth of the character described in the prior patents referred to. Said tool is shown on a larger scale in Fig. 13. Like the tool shown in Fig. 12, it is made of two units l00a and I001) eachhaving teeth with con-vex side faces alined is desired, ortne lccations helix anglethan the tool.

with the teeth of the other section and having cutting edges on their inner ends. Although the teeth here shown are parallel to the axis of the tool, they may be arranged helically for finishing spur gears or helical external gears of different A work piece H)! is mounted on the spindle 2| in place of the tool 33, the spindle holder is adjusted to bring the axis of spindle 2| into parallelism with the path of its reciprocation, and the holder 96 is made fast to the table 46 in a position which brings the tool and gear into mesh at a skew angle equal to the helix angle of the teethof this work piece and with the common perpendicular to the axes of the tool and work piece in a position intermediate the ends of the tool, and also between the ends of the work piece l! when the spindle carriage l4 isat or nearmid stroke. Such common perpendicular is located at A in Fig. 11 (as also in Fig. 6) and coincides with the axis of angular adjustment of holder when the carriage or slide I 4 is in the position there shown. In all other positions of the carriage the said common perpendicular and axis of adjustment are parallel to one another.

The characteristics of tools adapted for finishing external gears are shown in Figs. 14 and 15. They are substantially like the tools for finishing internal gears except that their teeth t and t have concave instead of convex side faces, whereby extended lengthwise contact may be made with the teeth of the work gear. The teeth t of the tool shown in Fig. 15 difier from the teeth t shown in Fig. 4 in that they are helical instead of in an arrangement similar to spur gears.

In all forms of tool embodying the bowed face curvature, whether convex or concave, the curves of alined teeth of the assembled units are continuation curves. That is, in the convex form, the least thickness of the teeth is at the ends of from the ends; while in the concave form, the

greatest thickness is at the ends and the thickness diminishes inwardly from the ends.

The illustrations herein show two of the many different work or tool holders which may be used with this machine and two of the many positions in which such holders may be located. In these illustrations the holders are fastened to the table of the upright slide by screws. They may be thus secured inany position suitable to bring straight toothed tools (i. e., tools in which the teeth are parallel to the axis) into mesh with conjugate helical work gears of any helix angle, or helical tools into mesh with straight toothed work gears or with helical work gears of different helix angles from the tools, whether the tools or the work gears have external or internal teeth; while the capacity for adjustment of the slide 43 permits tools and work gears of different diameters to be thus brought into mesh. In commercial practice machines of the design here illus trated are provided with a number of holders like or analogous to the holders 45 and 9B, and tapped holes are cut in the table 46 in locations suitable for correctly positioning such holders. It is within my contemplation, however, to provide the slide 43 with guide means corresponding to those of the carriage M and holder 28, or with a turn table adjustable to any angle about a vertical axis, or other suitable equivalent means whereby difierent holders or carriers may be adjusted to any position required for the mesh of different tools and work pieces in the manner described.

I wish to make it plainly understood that the descriptive terms used in the foregoing specification and the appended claims which define the relations of the parts of the machine with respect to the horizontal and vertical, arenot intended to have any limiting efiect. These terms are convenient for clear and concise description, and are used only for that purpose. So far as the principles which I claim are concerned, the machine and its parts maybe disposed in any relation to the horizon provided correlation between the parts equivalent to the rangement of the spindle carriage to move horizontally is of advantage because the effect of its weight is equal on its movements in both directions; and the vertical or upright arrangement of the slide 43 is of advantage because it enables gravity to move this slide in one direction; but these are not essential or controlling features and it would be no departure from the invention to provide mechanical means for retracting the slide in other arrangements.

What I claim and desire to secure by Letters Patent is:

1. A machine for finishing gears by the action of a conjugate gear-like tool running in mesh therewith when the axes of said gear and tool are non-parallel and non-intersecting, comprising a reciprocatable carriage, a spindle holder on said carriage, a spindle rotatably mounted in said holder and protruding therefrom having provisions for mounting coaxially such tool or work gear, a slide mounted with capacity for moving in a path transverse to that of said carriage, and a work holder supported on said slide and adapted to support rotatably a gear element in mesh with a gear element on said spindle, said spindle holder being mounted with provision for angular adjustment on the carriage about an axis perpendicular to the axis of the spindle and to the path of reciprocation of the carriage.

2. A machine for finishing gears by the action of a conjugate gear-like tool running in mesh therewith when the axes of said gear and tool are non-parallel and non-intersecting, comprising a reciprocatable carriage, means for limiting the reciprocations of the carriage to a given path, a spindle holder on said carriage, a spindle rotatably mounted in said holder and protruding therefrom having provisions for mounting coaxially such tool or Work gear, a slide mounted with capacity for moving in a path transverse to that of said carriage, and a work holder supported on said slide and adapted to support rotatably a gear element in mesh with a gear element on said spindle, said holder and the gear element supported therebybeing located so that the common perpendicular to the axes of the gear element and spindle is intermediate the ends of both intermeshing gear elements when the carriage is at an intermediate point in its path of travel, and the spindle holder being adjustably connected to the carriage for angular adjustment about an axis which coincides with said common perpendicular when the carriage is at said intermediate point.

3. A gear finishing machine comprising a base,

' a carriage movable back and forth on said base in a fixed path, a slide movable back and forth on the base in a path intersecting the path of said carriage, supporting means on said carriage and slide respectively adapted to hold rotatably a gear to be finished and a gear-like finishing tool respectively, in mesh with one another with their axes non-parallel and non-intersecting, means for reciprocating said carriage between fixed limits, an abutment for said slide arranged to retain the slide in a given position relative to the path of the carriage during the operative traverse of the carriage, and adjusting means on theslide adapted to vary the position of the supporting means onthe slide with respect to the path of the supporting means on the carriage.

foregoing description is maintained. The "ar- 7 41 A gear finishing machine comprising a base, a carriage movable back and forth on said base in a fixed path, a slide movable back and forth on the base in a path'intersecting the path of said tatably mounted on said supporting structure to rotate about axes each parallel to a line obliquely intersecting the other, a tool in, the form of an external gear mounted on said spindle and having teeth conjugate to the teeth of an internal gearcoaxial with said holder, the side faces'of said tool teeth being longitudinally convex so as to make extended lengthwise contact with the teeth of said gear, and means for rotating the spindle.

17. A machine for finishing internal gears which comprises a holder adapted to support such a gear rotatably with provision for meshing with an external gear, a tool in the form of an external gear conjugate to such internal gear when located with its axis inclined to the axis of the work gear and in a different plane therefrom and in mesh with the gear, a rotatable work spindle on which said tool is coaxially mounted, and provisions for relatively adjusting said holder and spindle to bring them into position for effecting crossed axis mesh between the tool and internal gear; the teeth of the tool having longitudinally convex face curves of greater convexity than that which suffices to cause uniform bearing on the mating teeth of the work gear throughout the common length of the intermeshing teeth.

18. A gear finishing. machine comprising rotary holders adapted to support rotatably a tool in the form of an external gear and an external work gear respectively, said holders being located with their axes inclined to one another but in different planes, a tool mounted on one of said holders having teeth conjugate to the teeth of an external gear mounted on the other holder and its tooth faces being longitudinally concave on opposite sides with curvatures suflicient to effect extended bearing lengthwise on the mating teeth of the work gear, and means for rotating one of said holders.

19. A gear finishing machine comprising rotary holders adapted to support rotatably a tool in the form of an external gear and an external work gear respectively, said holders being located with their axes inclined to one another but in different planes, a tool mounted on one of said holders having teeth conjugate to the teeth of an external gear mounted on the other holder and its tooth faces being longitudinally concave on opposite sides with curvatures suificient to eiTect extended bearing lengthwise with the work gear teeth, but of less concavity than that which would effect uniform bearing throughout the entire common length of such mating teeth, and means for rotating one of said holders.

20. A machine for finishing gears by the action of a gear-like tool conjugate to the gear to be finished and running in mesh therewith when the axes of said gear and tool are non-parallel and non-intersecting, comprising a base, a carriage mounted on the top of said base to reciprocate crosswise thereof, a spindle supported rotatably by said carriage and protruding at one end therefrom from the side of the base, having provisions for mounting such tool or gear on its protruding end, a slide mounted on the side of the base from which the spindle protrudes with provisions for movement up and down in a path crossing the protruding end of the spindle, rotatable means supported on said slide and adapted to hold rotatably a gear to be finished or a tool in mesh with the tool or gear respectively on the spindle, the axis of said rotatabl holding means being displaced from the axis of the spindle along the path of the slide in a position such that said axes neither intersect nor coincide, and a rigid abutment for the slide maintaining a prescribed distance between said axes during traverse of the carriage.

EDWARD W. MILLER. 

